1. Field
One or more embodiments described herein relate to a flexible display device.
2. Description of the Related Art
A variety of flat panel displays have been developed. Examples include a liquid crystal display and an organic light emitting display.
A liquid crystal display generally includes an upper panel where a common electrode and a color filter are formed, a lower panel where a thin film transistor and a pixel electrode are formed, and a liquid crystal layer between the upper and lower panels. An electric field is generated in the liquid crystal layer when a potential difference exists between the pixel electrode and the common electrode. The electric field determines the alignment direction of liquid crystal molecules in the liquid crystal layer. The alignment direction, in turn, determines the transmittance of incident light for purposes of forming an image.
An organic light emitting display device includes a hole injection electrode (anode), an electron injection electrode (cathode), and an organic emission layer between the hole injection electrode and the electron injection electrode. This type of display is a self-emissive display. In operation, holes injected from the anode and electrons injected from the cathode recombine in the organic emission layer to emit light.
These display devices may be formed using glass substrates. A glass substrate is heavy and fragile and therefore limits portability. Also, this type of substrate is not ideal for large-screen.
Display devices have been developed which use plastic substrates, which are light, strong, and flexible. In particular, an organic light emitting display device has been developed as a flexible display device or a stretchable display device. These display devices use substrates made of flexible or stretchable material, such as plastic or foil. These substrates are suitable for fabricating thin, light displays with large area screens.